Bottle assemblies, such as infant or nursing bottle assemblies, typically have multiple components including a bottle, a nipple, a collar for securing the nipple to the bottle (the nipple and collar sometimes collectively defining a collar assembly), and a cap for covering the nipple when the bottle is not in use. The nipple typically has one or more openings for allowing liquid contained within the bottle to exit through the nipple and into an infant's mouth for consumption by the infant (or young child). During use, the infant places an end of the nipple in their mouth and sucks on the nipple to withdraw the liquid contained within the bottle.
At least some bottle assemblies include a removable vent assembly that can be positioned within the bottle. For example, at least some bottle assemblies comprise a removable vent assembly configured to sit on an annular rim defining an open end of the bottle which permits venting of the bottle during use. In these bottle assemblies, the vent assembly allows air to enter the bottle while the infant consumes the liquid through the nipple, thus alleviating or reducing the formation of a vacuum within the bottle during nursing. The vent assembly typically seats, at least in part, on the rim of the bottle and a collar assembly including a collar and nipple are together threadably secured down over the vent assembly to external threads on the neck of the bottle.
The vent assemblies, therefore, are positioned between the bottle and the nipple, and include an air vent feature for venting air from the interior of the bottle to the ambient environment exterior of the bottle assembly. The vent assembly includes a vent tube that extends into the interior of the bottle to a location proximate the bottom of the bottle. In use, the bottle assembly is typically tilted at a downward angle so that the contents of the bottle flow through openings in the vent assembly into the nipple. In addition, a portion of the contents of the bottle flow into the vent tube. The vent tube has a receptacle sized to receive the liquid in the vent tube. When feeding is complete, the bottle is tilted back upright. As such, the liquid remaining in receptacle is intended to flow back through the vent tube and back into the bottle. However, with some known bottles, air may become trapped in the vent tube between the liquid flowing back into the bottle from the receptacle, and the liquid flowing into the vent tube from the bottle, thereby forming an air bubble in the vent tube. The air bubble may prevent the liquid from properly flowing back into the bottle from the receptacle. When the bottle is used again, the liquid above the air bubble flows back in the receptacle, plus additional liquid in the vent tube flows into the receptacle. As a result, the risk of leakage from the bottle assembly is increased.
There is a need, therefore, for a bottle assembly, and in particular a vented bottle assembly, in which the vent assembly facilitates the flow back of liquid into the bottle when the bottle is turned upright after feeding.